No idea what is going on here. Here is the query, right from phpMyAdmin:
SELECT * FROM `la_schedule` WHERE \'start_date\' >\'2012-11-18\';
In your statement, you are comparing a string called start_date with the time.
If start_date is a column, it should either be
SELECT * FROM `la_schedule` WHERE start_date >'2012-11-18';
(no apostrophe) or
SELECT * FROM `la_schedule` WHERE `start_date` >'2012-11-18';
(with backticks).
Hope this helps.